Refrigerant Line Muffler

ABSTRACT

Systems and methods are disclosed that include providing a refrigerant line muffler in a heating, ventilation, and/or air-conditioning (HVAC) system that reduces noise and/or vibration over a range of frequencies that result from operating a variable speed compressor. The refrigerant line muffler divides the flow of refrigerant from the compressor discharge into a first flowpath and a second flowpath, the second flowpath configured to cause a phase shift of a pressure wave of refrigerant flowing through the second flowpath relative to a pressure wave of refrigerant flowing through the first flowpath and cause destructive interference between a pressure wave of refrigerant flowing through the first flowpath and the pressure wave of refrigerant flowing through the second flowpath when first flowpath and second flowpath rejoin into single flowpath at outlet.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application No. 62/151,195 filed on Apr. 22, 2015 by Stephen Stewart Hancock, and entitled “Refrigerant Line Muffler,” the disclosure of which is hereby incorporated by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

Heating, ventilation, and/or air conditioning (HVAC) systems may generally be used in residential and/or commercial structures to provide heating and/or cooling to climate-controlled areas within these structures. Some HVAC systems may comprise a refrigerant line muffler. A refrigerant line muffler may be configured to induce destructive interference between entering and reflected waves within the refrigerant line muffler to reduce transmitted pressure pulses caused by a compressor passing the refrigerant through the refrigerant circuit of the HVAC system. Another common strategy for reducing pressure pulsations is to pass the fluid through a typically porous media that reduces the amplitude of the pressure wave by absorbing at least some of the wave's energy. However, some HVAC systems use variable speed compressors, which can emit pressure pulses over a much wider frequency range than single speed compressors. Additionally, variable speed compressors can also emit pressure pulses at much lower frequencies than single speed compressors, which are more difficult for reflective and absorptive mufflers to attenuate.

SUMMARY

In some embodiments of the disclosure, a refrigerant line muffler is disclosed as comprising: a first flowpath that extends from an inlet to an outlet; a second flowpath disposed between the inlet and the outlet, wherein the second flowpath is configured to cause a phase shift of a pressure wave of refrigerant flowing through the second flowpath relative to a pressure wave of refrigerant flowing through the first flowpath.

In other embodiments of the disclosure, a heating, ventilation, and/or air conditioning (HVAC) system is disclosed as comprising: a compressor comprising a compressor discharge; and a refrigerant line muffler disposed at the compressor discharge, the refrigerant line muffler comprising: a first flowpath that extends from an inlet to an outlet; a second flowpath disposed between the inlet and the outlet, wherein the second flowpath is configured to cause a phase shift of a pressure wave of refrigerant flowing through the second flowpath relative to a pressure wave of refrigerant flowing through the first flowpath.

In yet other embodiments of the disclosure, a method of operating a heating, ventilation, and/or air conditioning (HVAC) system is disclosed as comprising: discharging refrigerant from a compressor into a single flowpath; dividing the flow of refrigerant into a first flowpath and a second flowpath; rejoining the first flowpath and the second flowpath into a single flowpath; and causing destructive interference between pressure pulse waves of refrigerant exiting the first flowpath and the second flowpath.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description:

FIG. 1 is a schematic diagram of an HVAC system having a refrigerant line muffler according to an embodiment of the disclosure;

FIG. 2 is an oblique view of the refrigerant line muffler of FIG. 1 according to an embodiment of the disclosure;

FIG. 3 is a chart showing the average attenuation of the refrigerant line muffler of FIGS. 1 and 2 according to an embodiment of the disclosure;

FIG. 4 is an oblique view of a dual loop refrigerant line muffler according to an embodiment of the disclosure;

FIG. 5 is a chart showing the average attenuation of the refrigerant line muffler of FIG. 4 according to an embodiment of the disclosure;

FIG. 6 is a refrigerant line muffler according to another embodiment of the disclosure;

FIG. 7 is an orthogonal side view of a refrigerant line muffler according to yet another embodiment of the disclosure;

FIG. 8 is an orthogonal top view of the refrigerant line muffler of FIG. 7 according to an embodiment of the disclosure; and

FIG. 9 is a flowchart of a method of operating a heating, ventilation, and/or air conditioning (HVAC) system according to an embodiment of the disclosure.

DETAILED DESCRIPTION

In some cases, it may be desirable to provide a refrigerant line muffler in a heating, ventilation, and/or air-conditioning (HVAC) system. For example, where an HVAC system uses a variable speed compressor to pump refrigerant through the refrigerant circuit, it may be desirable to provide a refrigerant line muffler close to the discharge port of the compressor to attenuate a wide range of frequencies and/or low frequencies of pressure pulses that are specific to variable speed compressors. In some embodiments, systems and methods are disclosed that comprise providing a refrigerant line muffler that is configured to attenuate low frequency pressure pulses specific to using a variable speed compressor in an HVAC system. In some embodiments, the refrigerant line muffler may be used in an HVAC system, including, but not limited to, a heat pump system. In alternative embodiments, however, the refrigerant line muffler may be used in an air-conditioning system.

Referring now to FIG. 1, a schematic diagram of an HVAC system 100 is shown according to an embodiment of the disclosure. HVAC system 100 generally comprises an indoor unit 102, an outdoor unit 104, and a system controller 106. The system controller 106 may generally control operation of the indoor unit 102 and/or the outdoor unit 104. As shown, the HVAC system 100 is a so-called heat pump system that may be selectively operated to implement one or more substantially closed thermodynamic refrigeration cycles to provide a cooling functionality and/or a heating functionality.

Indoor unit 102 generally comprises an indoor heat exchanger 108, an indoor fan 110, and an indoor metering device 112. Indoor heat exchanger 108 is a plate fin heat exchanger configured to allow heat exchange between refrigerant carried within internal tubing of the indoor heat exchanger 108 and fluids that contact the indoor heat exchanger 108 but that are kept segregated from the refrigerant. In other embodiments, indoor heat exchanger 108 may comprise a spine fin heat exchanger, a microchannel heat exchanger, or any other suitable type of heat exchanger.

The indoor fan 110 is a centrifugal blower comprising a blower housing, a blower impeller at least partially disposed within the blower housing, and a blower motor configured to selectively rotate the blower impeller. In other embodiments, the indoor fan 110 may comprise a centrifugal, mixed-flow fan and/or any other suitable type of fan. The indoor fan 110 is configured as a modulating and/or variable speed fan capable of being operated at many speeds over one or more ranges of speeds. In other embodiments, the indoor fan 110 may be configured as a multiple speed fan capable of being operated at a plurality of operating speeds by selectively electrically powering different ones of multiple electromagnetic windings of a motor of the indoor fan 110. In yet other embodiments, the indoor fan 110 may be a single speed fan.

The indoor metering device 112 is an electronically controlled motor driven electronic expansion valve (EEV). In alternative embodiments, the indoor metering device 112 may comprise a thermostatic expansion valve, a capillary tube assembly, and/or any other suitable metering device. The indoor metering device 112 may comprise and/or be associated with a refrigerant check valve and/or refrigerant bypass for use when a direction of refrigerant flow through the indoor metering device 112 is such that the indoor metering device 112 is not intended to meter or otherwise substantially restrict flow of the refrigerant through the indoor metering device 112.

Outdoor unit 104 generally comprises an outdoor heat exchanger 114, a compressor 116, an outdoor fan 118, an outdoor metering device 120, and a reversing valve 122. In some embodiments, the outdoor unit 104 may also comprise a refrigerant line muffler 200. Outdoor heat exchanger 114 is a microchannel heat exchanger configured to allow heat exchange between refrigerant carried within internal passages of the outdoor heat exchanger 114 and fluids that contact the outdoor heat exchanger 114 but that are kept segregated from the refrigerant. In other embodiments, outdoor heat exchanger 114 may comprise a plate fin heat exchanger, a spine fin heat exchanger, or any other suitable type of heat exchanger.

The compressor 116 generally comprises a compressor discharge 117 where refrigerant may exit the compressor 116 and a compressor inlet 119 where refrigerant may be returned to the compressor 116 after passing through a refrigerant circuit. In some embodiments, the compressor 116 is a multiple speed scroll type compressor configured to selectively pump refrigerant at a plurality of mass flow rates. In alternative embodiments, the compressor 116 may comprise a modulating compressor capable of operation over one or more speed ranges, a reciprocating type compressor, a single speed compressor, and/or any other suitable refrigerant compressor and/or refrigerant pump.

The refrigerant line muffler 200 may generally be installed at and/or near the compressor discharge 117. The refrigerant line muffler 200 may be configured to attenuate specific frequencies of pressure pulses associated with utilizing a variable speed compressor, such as compressor 116, to pump refrigerant through the refrigerant circuit of the HVAC system 100. In other embodiments, the refrigerant line muffler 200 may also be configured to attenuate specifics frequencies of pressure pulses associated with utilizing a single speed and/or a multiple-fixed speed compressor. The refrigerant line muffler 200 may generally be configured to split the flow of refrigerant through a first fluid flowpath and a second fluid flowpath, that when rejoined at a downstream end of the refrigerant line muffler 200, causes destructive interference between pressure pulses through each of the first fluid path and the second fluid path in the refrigerant line muffler 200. Accordingly, the refrigerant line muffler 200 may be configured to reduce noise and/or vibrations emitted by the flowing refrigerant, and thus prevent such noise and/or vibrations from entering the outdoor heat exchanger 114, the indoor unit 102, and/or the refrigerant line leading to a structure that is conditioned by the HVAC system 100. Additionally, in alternative embodiments, the refrigerant line muffler 200 may also be positioned at the suction side of the compressor 116 where pressure pulses caused by periodic low pressure pulses emanating from the compressor may present issues.

The outdoor fan 118 is an axial fan comprising a fan blade assembly and fan motor configured to selectively rotate the fan blade assembly. In other embodiments, the outdoor fan 118 may comprise a mixed-flow fan, a centrifugal blower, and/or any other suitable type of fan and/or blower. The outdoor fan 118 is configured as a modulating and/or variable speed fan capable of being operated at many speeds over one or more ranges of speeds. In other embodiments, the outdoor fan 118 may be configured as a multiple speed fan capable of being operated at a plurality of operating speeds by selectively electrically powering different ones of multiple electromagnetic windings of a motor of the outdoor fan 118. In yet other embodiments, the outdoor fan 118 may be a single speed fan.

The outdoor metering device 120 is a thermostatic expansion valve. In alternative embodiments, the outdoor metering device 120 may comprise an electronically controlled motor driven EEV similar to indoor metering device 112, a capillary tube assembly, and/or any other suitable metering device. The outdoor metering device 120 may comprise and/or be associated with a refrigerant check valve and/or refrigerant bypass for use when a direction of refrigerant flow through the outdoor metering device 120 is such that the outdoor metering device 120 is not intended to meter or otherwise substantially restrict flow of the refrigerant through the outdoor metering device 120.

The reversing valve 122 is a so-called four-way reversing valve. The reversing valve 122 may be selectively controlled to alter a flow path of refrigerant in the HVAC system 100 as described in greater detail below. The reversing valve 122 may comprise an electrical solenoid or other device configured to selectively move a component of the reversing valve 122 between operational positions.

The system controller 106 may generally comprise a touchscreen interface for displaying information and for receiving user inputs. The system controller 106 may display information related to the operation of the HVAC system 100 and may receive user inputs related to operation of the HVAC system 100. However, the system controller 106 may further be operable to display information and receive user inputs tangentially and/or unrelated to operation of the HVAC system 100. In some embodiments, the system controller 106 may not comprise a display and may derive all information from inputs from remote sensors and remote configuration tools. In some embodiments, the system controller 106 may comprise a temperature sensor and may further be configured to control heating and/or cooling of zones associated with the HVAC system 100. In some embodiments, the system controller 106 may be configured as a thermostat for controlling supply of conditioned air to zones associated with the HVAC system 100.

In some embodiments, the system controller 106 may also selectively communicate with an indoor controller 124 of the indoor unit 102, with an outdoor controller 126 of the outdoor unit 104, and/or with other components of the HVAC system 100. In some embodiments, the system controller 106 may be configured for selective bidirectional communication over a communication bus 128. In some embodiments, portions of the communication bus 128 may comprise a three-wire connection suitable for communicating messages between the system controller 106 and one or more of the HVAC system 100 components configured for interfacing with the communication bus 128. Still further, the system controller 106 may be configured to selectively communicate with HVAC system 100 components and/or any other device 130 via a communication network 132. In some embodiments, the communication network 132 may comprise a telephone network, and the other device 130 may comprise a telephone. In some embodiments, the communication network 132 may comprise the Internet, and the other device 130 may comprise a smartphone and/or other Internet-enabled mobile telecommunication device. In other embodiments, the communication network 132 may also comprise a remote server.

The indoor controller 124 may be carried by the indoor unit 102 and may be configured to receive information inputs, transmit information outputs, and otherwise communicate with the system controller 106, the outdoor controller 126, and/or any other device 130 via the communication bus 128 and/or any other suitable medium of communication. In some embodiments, the indoor controller 124 may be configured to communicate with an indoor personality module 134 that may comprise information related to the identification and/or operation of the indoor unit 102. In some embodiments, the indoor controller 124 may be configured to receive information related to a speed of the indoor fan 110, transmit a control output to an electric heat relay, transmit information regarding an indoor fan 110 volumetric flow-rate, communicate with and/or otherwise affect control over an air cleaner 136, and communicate with an indoor EEV controller 138. In some embodiments, the indoor controller 124 may be configured to communicate with an indoor fan controller 142 and/or otherwise affect control over operation of the indoor fan 110. In some embodiments, the indoor personality module 134 may comprise information related to the identification and/or operation of the indoor unit 102 and/or a position of the outdoor metering device 120.

In some embodiments, the indoor EEV controller 138 may be configured to receive information regarding temperatures and/or pressures of the refrigerant in the indoor unit 102. More specifically, the indoor EEV controller 138 may be configured to receive information regarding temperatures and pressures of refrigerant entering, exiting, and/or within the indoor heat exchanger 108. Further, the indoor EEV controller 138 may be configured to communicate with the indoor metering device 112 and/or otherwise affect control over the indoor metering device 112. The indoor EEV controller 138 may also be configured to communicate with the outdoor metering device 120 and/or otherwise affect control over the outdoor metering device 120.

The outdoor controller 126 may be carried by the outdoor unit 104 and may be configured to receive information inputs, transmit information outputs, and otherwise communicate with the system controller 106, the indoor controller 124, and/or any other device 130 via the communication bus 128 and/or any other suitable medium of communication. In some embodiments, the outdoor controller 126 may be configured to communicate with an outdoor personality module 140 that may comprise information related to the identification and/or operation of the outdoor unit 104. In some embodiments, the outdoor controller 126 may be configured to receive information related to an ambient temperature associated with the outdoor unit 104, information related to a temperature of the outdoor heat exchanger 114, and/or information related to refrigerant temperatures and/or pressures of refrigerant entering, exiting, and/or within the outdoor heat exchanger 114 and/or the compressor 116. In some embodiments, the outdoor controller 126 may be configured to transmit information related to monitoring, communicating with, and/or otherwise affecting control over the outdoor fan 118, a compressor sump heater, a solenoid of the reversing valve 122, a relay associated with adjusting and/or monitoring a refrigerant charge of the HVAC system 100, a position of the indoor metering device 112, and/or a position of the outdoor metering device 120. The outdoor controller 126 may further be configured to communicate with a compressor drive controller 144 that is configured to electrically power and/or control the compressor 116.

The HVAC system 100 is shown configured for operating in a so-called cooling mode in which heat is absorbed by refrigerant at the indoor heat exchanger 108 and heat is rejected from the refrigerant at the outdoor heat exchanger 114. In some embodiments, the compressor 116 may be operated to compress refrigerant and pump the relatively high temperature and high pressure compressed refrigerant from the compressor 116 through the refrigerant line muffler 200, through the reversing valve 122, and to the outdoor heat exchanger 114. As the refrigerant is passed through the outdoor heat exchanger 114, the outdoor fan 118 may be operated to move air into contact with the outdoor heat exchanger 114, thereby transferring heat from the refrigerant to the air surrounding the outdoor heat exchanger 114. The refrigerant leaving the outdoor heat exchanger 114 may primarily comprise liquid phase refrigerant, and the refrigerant may flow from the outdoor heat exchanger 114 to the indoor metering device 112 through and/or around the outdoor metering device 120 which does not substantially impede flow of the refrigerant in the cooling mode. The indoor metering device 112 may meter passage of the refrigerant through the indoor metering device 112 so that the refrigerant downstream of the indoor metering device 112 is at a lower pressure than the refrigerant upstream of the indoor metering device 112. The pressure differential across the indoor metering device 112 allows the refrigerant downstream of the indoor metering device 112 to expand and/or at least partially convert to a two-phase (vapor and gas) mixture. The two phase refrigerant may enter the indoor heat exchanger 108. As the refrigerant is passed through the indoor heat exchanger 108, the indoor fan 110 may be operated to move air into contact with the indoor heat exchanger 108, thereby transferring heat to the refrigerant from the air surrounding the indoor heat exchanger 108, and causing evaporation of the liquid portion of the two phase mixture. The vapor-phase refrigerant may thereafter re-enter the compressor 116 after passing through the reversing valve 122.

To operate the HVAC system 100 in the so-called heating mode, the reversing valve 122 may be controlled to alter the flow path of the refrigerant, the indoor metering device 112 may be disabled and/or bypassed, and the outdoor metering device 120 may be enabled. In the heating mode, refrigerant may flow from the compressor 116 to the indoor heat exchanger 108 through the reversing valve 122, the refrigerant may be substantially unaffected by the indoor metering device 112, the refrigerant may experience a pressure differential across the outdoor metering device 120, the refrigerant may pass through the outdoor heat exchanger 114, and the refrigerant may re-enter the compressor 116 after passing through the reversing valve 122. Most generally, operation of the HVAC system 100 in the heating mode reverses the roles of the indoor heat exchanger 108 and the outdoor heat exchanger 114 as compared to their operation in the cooling mode.

Referring now to FIG. 2, an oblique view of the refrigerant line muffler 200 of FIG. 1 is shown according to an embodiment of the disclosure. Refrigerant line muffler 200 comprises an inlet 202, an outlet 204, a first flowpath 206, and a second flowpath 208. Most generally, the refrigerant line muffler 200 is configured to attenuate a range of frequencies of pressure pulses associated with utilizing a variable speed compressor, such as compressor 116 of FIG. 1, to pump refrigerant through the refrigerant circuit of the HVAC system 100 of FIG. 1. However, as the refrigerant line muffler 200 is designed to minimize transmission of a single wavelength and its integer multiples, it is applicable to a variety of compressor types including single-speed, multiple-fixed-speed, and/or variable speed compressor types. The refrigerant line muffler 200 may generally be formed from copper tubing. However, in alternative embodiments, the refrigerant line muffler 200 may be formed from any other material capable of carrying refrigerant through each of the first flowpath 206 and the second flowpath 208. Furthermore, it will be appreciated that the first flowpath 206 and the second flowpath 208 may comprise substantially similar diameter tubing. The refrigerant line muffler 200 may receive refrigerant from the compressor discharge 117 of compressor 116 through the inlet 202. The inlet 202 may branch into the first flowpath 206 and the second flowpath 208 to split the flow of refrigerant through the first flowpath 206 and the second flowpath 208, respectively. Refrigerant may travel through each of the first flowpath 206 and the second flowpath 208 before rejoining into a single flowpath and exiting the refrigerant line muffler 200 through the outlet 204.

The first flowpath 206 may generally comprise a shorter length than the second flowpath 208. The first flowpath 206 may generally comprise a substantially straight, linear flowpath. However, in other embodiments, the first flowpath 206 may comprise any other shaped flowpath. To accommodate the substantially longer length, the second flowpath 208 may be coiled into at least one coil disposed between the inlet 202 and the outlet 204. In some embodiments, however, the second flowpath may comprise a plurality of coils having substantially the same diameter and be substantially aligned axially and/or be overlapped. However, in alternative embodiments, the coils may comprise different diameters, be substantially concentric, and/or any other configuration.

The length of the second flowpath 208 may generally be determined by the wavelength of the pressure pulses that the refrigerant line muffler 200 is configured to attenuate. More specifically, the second flowpath 208 may comprise a length that is longer than the first flowpath 206 by about one-half (½) of the wavelength of the pressure pulse sought to be attenuated, such that when the first flowpath 206 and the second flowpath 208 rejoin at the outlet 204, the wave of the pressure pulse traveling through the second flowpath 208 is phase-shifted about 180 degrees with respect to the wave of the pressure pulse traveling through the first flowpath 206. By phase-shifting the wave of the pressure pulse through the second flowpath 208 about 180 degrees, destructive interference between the pressure pulse in the first flowpath 206 and the second flowpath 208 results upon recombining into a single flowpath at the outlet 204. The destructive interference caused by phase-shifting the wave of the pressure pulse in the second flowpath reduces noise and/or vibrations emitted by the flowing refrigerant leaving the refrigerant line muffler 200.

In some embodiments, the refrigerant line muffler 200 may be configured to phase-shift the wave of the pressure pulse traveling through the second flowpath 208 by about 180 degrees. However, in other embodiments, the refrigerant line muffler 200 may be configured to shift the wave of the pressure pulse traveling through the second flowpath 208 by at least about 178 degrees, by at least about 176 degrees, and/or by at least about 174 degrees. Additionally, while the refrigerant line muffler 200 may be configured to target a specific frequency to attenuate, it will be appreciated that the refrigerant line muffler may attenuate a range of frequencies since at least partial destruction of the pressure wave will occur for all wavelengths except those that are even-integer multiples of the difference between the first and second flowpaths, 206 and 208, respectively. The refrigerant line muffler 200 is generally configured for use in an HVAC system comprising a variable speed compressor. Because variable speed compressors generally produce pressure pulses having a larger range of frequencies and/or lower frequencies that are difficult to attenuate as compared to single speed compressors, the refrigerant line muffler 200 is configured to attenuate such low frequencies and/or a very large range of frequencies as compared to conventional mufflers designed for operation in single speed HVAC systems. For example, the refrigerant line muffler 200 may be configured to attenuate frequencies as low as about 40 Hz while providing a substantially low pressure drop across the refrigerant line muffler 200. Additionally, the use of coils for the second flowpath 208 may also provide a compact size for the refrigerant line muffler 200.

Referring now to FIG. 3, a chart 300 showing the average attenuation of the refrigerant line muffler 200 of FIGS. 1 and 2 is shown according to an embodiment of the disclosure. Chart 300 depicts frequency along the x-axis and the ratio of outlet to inlet pressure wave amplitude along the y-axis. The target frequency for this embodiment is about 67 Hz. Transmitted wave amplitude ratio ranges from 0, which is total cancellation of the pressure pulse wave, to 1, which is no cancellation of the wave. Chart 300 also includes attenuation line 302 which illustrates the attenuated vibration amplitude (attenuated amplitude equals 1-transmitted amplitude) over an operating frequency range of 40 Hz to 93 Hz of a representative variable speed compressor. Accordingly, attenuation line 302 illustrates that the refrigerant line muffler 200 may provide an average wave amplitude attenuation of about 87.5% over the operating frequency range of 40 Hz to 93 Hz, with full attenuation of the pressure pulse wave at about 67 Hz. It will be appreciated that while attenuation line 302 depicts complete attenuation of a single wavelength at about 67 Hz by the refrigerant line muffler 200, the refrigerant line muffler 200 provides partial attenuation over the full spectrum of frequencies (40 Hz to 93 Hz) for which the refrigerant line muffler 200 was designed. Additionally, it will be appreciated that while refrigerant line muffler 200 provides an average attenuation of about 87.5%, the refrigerant line muffler 200 may be configured to provide an average attenuation of at least about 80%, at least about 85%, at least about 87.5%, at least about 90%, at least about 92.5%, and/or at least about 95%.

Referring now to FIG. 4, an oblique view of a dual loop refrigerant line muffler 400 is shown according to an embodiment of the disclosure. Refrigerant line muffler 400 generally comprises a first muffler 401 and a second muffler 409 disposed downstream with respect to the flow of refrigerant through the refrigerant line muffler 400. Muffler 401 may generally be substantially similar to refrigerant line muffler 200 and comprise an inlet 402, and outlet 404, a first flowpath 406, and a second flowpath 408 and be configured to attenuate a first range of frequencies of pressure pulses associated with utilizing a variable speed compressor by causing destructive interference in a manner substantially similar to that of refrigerant line muffler 200. In some embodiments, first muffler 401 may be refrigerant line muffler 200. Additionally, second muffler 409 may also be substantially similar to refrigerant line muffler 200 and comprise an inlet 410, an outlet 412, a first flowpath 414, and a second flowpath 416 and be configured to attenuate a second range of frequencies of pressure pulses associated with utilizing a variable speed compressor by causing destructive interference in a manner substantially similar to that of refrigerant line muffler 200. In some embodiments, the first muffler 401 may be configured to attenuate a lower range of frequencies than the second muffler 409. However, in other embodiments, the first muffler 401 may be configured to attenuate a higher range of frequencies than the second muffler 409. It will be appreciated that the first frequency range attenuated by the first muffler 401 and the second frequency range attenuated by the second muffler 409 may overlap.

Referring now to FIG. 5, a chart 500 showing the average attenuation of the refrigerant line muffler 400 of FIG. 4 is shown according to an embodiment of the disclosure. Chart 500 depicts frequency along the x-axis and the ratio of outlet to inlet pressure wave amplitude along the y-axis. Chart 500 includes attenuation line 502 which illustrates the attenuated pressure wave amplitude over an operating frequency range of 40 Hz to 93 Hz of a representative variable speed compressor. Accordingly, attenuation line 502 illustrates that the refrigerant line muffler 400 may provide an average amplitude attenuation of about 98.5% over the operating frequency range of 40 Hz to 93 Hz. Attenuation line 502 illustrates full attenuation of the pressure pulse wave at about 48 and 83 Hz. Additionally, it will be appreciated that while refrigerant line muffler 400 provides an average attenuation of about 98.5%, the refrigerant line muffler 200 may be configured to provide an average attenuation of at least about 95%, at least about 97.5%, at least about 98.5%, and/or at least about 99.5%.

Referring now to FIG. 6, an orthogonal view of a refrigerant line muffler 600 is shown according to another embodiment of the disclosure. Refrigerant line muffler 600 may generally be similar to refrigerant line muffler 200 and comprise an inlet 602, an outlet 604, a first flowpath 606, and a second flowpath 608. Refrigerant line muffler 600 may also be configured to attenuate a range of frequencies of pressure pulses associated with utilizing a variable speed compressor by causing destructive interference in a manner substantially similar to that of refrigerant line muffler 200. However, as opposed to refrigerant line muffler 200, refrigerant line muffler 600 comprises a plurality of coils 610, 612 in the second flowpath 608 that are not overlapped.

After refrigerant is split into the first flowpath 606 and the second flowpath 608, refrigerant may travel through each of the first flowpath 606 and the second flowpath 608, respectively. Refrigerant entering the second flowpath 608 may generally flow through the first coil 610, enter a substantially straight, linear flowpath 611 that is tangent to each of the first coil 610 and the second coil 612, and thereafter enter the second coil 612 before rejoining with the first flowpath 606 in the outlet 604 to cause the destructive interference necessary to attenuate noise and/or vibration. In some embodiments, coils 610, 612 comprise substantially similar diameters and may be substantially symmetric about a longitudinal axis that extends axially through the first flowpath 606. In an example, the first flowpath 606 may comprise about a 2 inch length. Each of the coils 610, 612 may comprise about an 8.125 inch diameter, with a 6 inch length of linear tubing between tangents of the coils 610, 612 that results in the second flowpath 608 comprising about a 54 inch length. However, in alternative embodiments, the coils 610, 612 may comprise different diameters while still maintaining the difference between the second and first flowpath lengths equal to ½ of the wavelength of maximum attenuation to cause destructive interference to attenuate noise and/or vibration.

Referring now to FIGS. 7 and 8, an orthogonal side view and an orthogonal top view of a refrigerant line muffler 700 are shown according to another embodiment of the disclosure. Refrigerant line muffler 700 may generally be substantially similar to refrigerant line muffler 200 and/or refrigerant line muffler 600 and comprises an inlet 702, an outlet 704, a first flowpath 706, and a second flowpath 708. Refrigerant line muffler 700 may also be configured to attenuate a range of frequencies of pressure pulses associated with utilizing a variable speed compressor by causing destructive interference in a manner substantially similar to that of refrigerant line mufflers 200, 600. However, as opposed to refrigerant line mufflers 200, 600, refrigerant line muffler 700 comprises an orthogonal branch 710 and an orthogonal joinder 712.

The first flowpath 706 may generally form a straight, linear flowpath that extends from the inlet 702 to the outlet 704. The second flowpath 708 may generally branch orthogonally at the orthogonal branch 710 from the inlet 702. The second flowpath 708 may generally form a plurality of coils that wind radially around the first flowpath 706 and then rejoin orthogonally to the first flowpath 706 at the orthogonal joinder 712. More specifically, the second flowpath 708 may branch orthogonally from the first flowpath 706 at the orthogonal branch 710 and extend from the orthogonal branch 710 for about 180 degrees at a first diameter and extend for a number of coils at a second diameter that is larger than the first diameter before extending for 180 degrees at the first diameter and rejoining the first flowpath 706 at the orthogonal joinder 712. In some embodiments, the first diameter may be about 4 inches, the second diameter may be about 4.85 inches, and the number of coils may be about 4.85 coils. However, in other embodiments, the first and second diameter may comprise any other dimension and the number of coils may be any other number of coils such that the length of the second flowpath 708 causes a phase shift of substantially about one-half (½) of the wavelength of the frequency of the pressure pulse sought to be attenuated, such that when the first flowpath 706 and the second flowpath 708 rejoin at the orthogonal joinder 712, the wave of the pressure pulse traveling through the second flowpath 708 is shifted about 180 degrees with respect to the wave of the pressure pulse traveling through the first flowpath 706, resulting in destructive interference between the pressure pulse in the first flowpath 706 and the second flowpath 708 upon recombining into a single flowpath at the orthogonal joinder 712.

Referring now to FIG. 9, a flowchart of a method 800 of operating a heating, ventilation, and/or air conditioning (HVAC) system is shown according to an embodiment of the disclosure. Method 800 may begin at block 802 by discharging refrigerant from a compressor into a single flowpath. The method 800 may continue at block 804 by dividing the flow of refrigerant into a first flowpath and a second flowpath. The method 800 may continue at block 806 by recombining the first flowpath and the second flowpath into a single flowpath. The method 800 may conclude at block 808 by causing destructive interference between pressure pulse waves of refrigerant exiting the first flowpath and the second flowpath. In some embodiments, causing destructive interference may be accomplished by providing a length of the second flowpath that results in a 180 degree phase shift of the pressure wave of refrigerant flowing through the second flowpath as compared to the pressure wave of refrigerant flowing through the first flowpath.

At least one embodiment is disclosed and variations, combinations, and/or modifications of the embodiment(s) and/or features of the embodiment(s) made by a person having ordinary skill in the art are within the scope of the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, R₁, and an upper limit, R_(u), is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=R_(l)+k*(R_(u)−R_(l)), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . , 50 percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 97 percent, 98 percent, 99 percent, or 100 percent. Unless otherwise stated, the term “about” shall mean plus or minus 10 percent of the subsequent value. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed. Use of the term “optionally” with respect to any element of a claim means that the element is required, or alternatively, the element is not required, both alternatives being within the scope of the claim. Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Accordingly, the scope of protection is not limited by the description set out above but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present invention. 

What is claimed is:
 1. A refrigerant line muffler, comprising: a first flowpath that extends from an inlet to an outlet; a second flowpath disposed between the inlet and the outlet, wherein the second flowpath is configured to cause a phase shift of a pressure wave of refrigerant flowing through the second flowpath relative to a pressure wave of refrigerant flowing through the first flowpath.
 2. The refrigerant line muffler of claim 1, wherein the phase shift of the pressure wave results in destructive interference between a pressure wave of refrigerant flowing through the first flowpath and the second flowpath when first flowpath and second flowpath rejoin into single flowpath at the outlet.
 3. The refrigerant line muffler of claim 1, wherein the second flowpath comprises a plurality of coils.
 4. The refrigerant line muffler of claim 1, further comprising: a second refrigerant line muffler connected in fluid communication with the outlet of the refrigerant line muffler.
 5. The refrigerant line muffler of claim 4, wherein the second refrigerant line muffler is configured to attenuate a higher range of frequencies than the refrigerant line muffler.
 6. The refrigerant line muffler of claim 1, wherein the second flowpath comprises a first coil and a second coil joined by a linear flowpath that is tangent to each of the first coil and the second coil.
 7. The refrigerant line muffler of claim 1, wherein the second flowpath branches from the first flowpath orthogonally at the inlet.
 8. The refrigerant line muffler of claim 7, wherein the second flowpath forms a plurality of coils that wind radially around the first flowpath.
 9. The refrigerant line muffler of claim 8, wherein the second flowpath rejoins the first flowpath orthogonally at the outlet.
 10. The refrigerant line muffler of claim 8, wherein the refrigerant line muffler provides an average attenuation of at least about 87.5% over a range of about 40 to about 93 Hz.
 11. A heating, ventilation, and/or air conditioning (HVAC) system, comprising: a compressor comprising a compressor discharge; and a refrigerant line muffler disposed at the compressor discharge, the refrigerant line muffler comprising: a first flowpath that extends from an inlet to an outlet; a second flowpath disposed between the inlet and the outlet, wherein the second flowpath is configured to cause a phase shift of a pressure wave of refrigerant flowing through the second flowpath relative to a pressure wave of refrigerant flowing through the first flowpath.
 12. The HVAC system of claim 11, wherein the phase shift of the pressure wave results in destructive interference between a pressure wave of refrigerant flowing through the first flowpath and the second flowpath when first flowpath and second flowpath rejoin into single flowpath at outlet.
 13. The HVAC system of claim 11, further comprising: a second refrigerant line muffler connected in fluid communication with the outlet of the refrigerant line muffler.
 14. The HVAC system of claim 13, wherein the second refrigerant line muffler is configured to attenuate a higher range of frequencies than the refrigerant line muffler.
 15. The HVAC system of claim 11, wherein the second flowpath comprises a first coil and a second coil joined by a linear flowpath that is tangent to each of the first coil and the second coil.
 16. The HVAC system of claim 11, wherein the second flowpath branches from the first flowpath orthogonally at the inlet, forms a plurality of coils that wind radially around the first flowpath, and rejoins to the first flowpath orthogonally at the outlet.
 17. A method of operating a heating, ventilation, and/or air conditioning (HVAC) system, comprising: discharging refrigerant from a compressor into a single flowpath; dividing the flow of refrigerant into a first flowpath and a second flowpath; rejoining the first flowpath and the second flowpath into a single flowpath; and causing destructive interference between pressure pulse waves of refrigerant exiting the first flowpath and the second flowpath.
 18. The method of claim 17, wherein causing the destructive interference is accomplished by providing a length of the second flowpath that results in a 180 degree phase shift of the pressure wave of refrigerant flowing through the second flowpath as compared to the pressure wave of refrigerant flowing through the first flowpath.
 19. The method of claim 17, wherein the second flowpath comprises a first coil and a second coil joined by a linear flowpath that is tangent to each of the first coil and the second coil.
 20. The method of claim 17, wherein the second flowpath branches from the first flowpath orthogonally at the inlet, forms a plurality of coils that wind radially around the first flowpath, and rejoins to the first flowpath orthogonally at the outlet. 